Backfire stop



March 1936. D. L. WERTZ- 2,033,364

BACKFIRE STOP Filed Nov; 24, 1951 0 I g P mum nw INVENTOR flwuel/LiUenbz BY my. W

TTORNEY rotation before the actuation of Patented Mar. 10, 1936 UNITED{STATES PATENT OFFICE Machine Company, Elmira tion of New York N. Y., acorpora- Application November 24 1931, Serial No. 5775123 8 Claims. (Cl.290-67) This invention relates to a back-fire stop and more particularlyto a device for restricting the recurrence of back-firing especially inconnection with automatic starting mechanism Back-firing of internalcombustion engines due to improperly timed ignition or other causes isundesirable particularly in connection with certain forms of automaticstarting mechanism which may operate to engage the starting mechanismduring the backward rotation of the engine thus putting unnecessarystresses on the parts of the starting mechanism.

It is an object of the present invention to provide a novel device forrestricting hack-fir of internal combustion engines.

It is another object of the invention to pro= vide such a device whichis adapted to prevent firing oi the engine for a interval after saidengine reverses its rotation.

It is a further object of the invention to provide in connection with anautomatic starting mechanism a novel device for ma the ignition systemor" an engine inoperative in order to allow the engineto come to restfrom reverse the starting mechanism.

Further objects and advantages will be apparent to those skilled in thisart ii the following description taken in connection saith. theaccompanying drawing in the figure semi-diagrammatic illustration partlysection oi a preferred embodiment of the in vention.

Referring to drawing, there is illustrated electrical system'ior aninternal combustion engine, not shotm, comprising a. starting circuit,an ignition circuit. The starting circuit comprises s. cattery l,grounded at 2 and connected by a lead 3 to an automatic startingmechanism indicated generally at 61 and corn prising an electricallyoperated starting switch 5 connected by a lead 6 to the starting motorSM which is grounded at 1. The starting switch 5 is arranged to beoperated by a solenoid 3- "which is included in a control circuitcompris ing a switch 9 which may be the ignition switch of the engine,leads II and I2, fixed contact [3, and movable contact 14 mounted onspring strip Iii which is grounded at IS. The arrangement oithis circuitis such that when contacts i3, is are closed, closure of the switch 5will cause energization .of solenoid 8 to close the starting switch 5.

Contact H is actuated by a solenoid plunger ii the action of which iscontrolled by avoltage coil IS, a current coil I9 in the startingcircuit, and a coil 2| energized by the generator G driven from theengine. The plunger i1 is normally maintained in its upper position asby means of a spring 22 and is retained in that position during crankingby the current coil 19, but when the engine starts the voltage coil 18overcomes the action of coil 19 and spring 22, retracting the plunger H.A lever 23 pivoted at one end as at 23! is provided with a pin 232 atintermediate point thereof adapted to extend laterally between a pair offlanges 233 23 5 suitably formed on the end of the magnetic plunger ll,whereby longitudinal motion of the plunger ii is caused to swing thelever 23 at its pivot. The free end of lever 23 is pro video with anengaging element 235 preferably form of a roller which is adapted to emta; cred weight element 26 fixed on the of the spring strip iii. Asuitable spring 6 is provided for normally holding the lever its upperor disengaged position, and for listing it to that position upon releaseof the magnetic plunger the usual operating conditions, the plunger isretained in its retracted position, by t generator coil Should theengine ones-inc, however, after an initial forward impulse of the crankshaft, suficient to disconnect starter, the generator will not retainthe plunger retracted. during the reverse rotation of the engine so thatreengagement of the starting mechanism will he allowed to occur.reengagement is dole. ed for apredetermined time virtue of the pendulousvibration of the 2 1 on the spring strip 115 which prevents efiectiveclosure of contact it during such vihraticn. "when the vibration ceases,however, "re-engagement will occur and if the back-firing condition hascontinued, such reengagement will excessive and possibly destructivestresses to he on the starting mechanism.

According to the present invention, means are provided for preventingthe continued backiiring of the engine during the time interval that thespring strip i5 is in vibration, whereby the engine will come to restbefore the reactua tion of the starting mechanism. As here shown,

this means is in the form of a set of contacts 25, 2S, 2?, '28 which areplaced in series in the primary circuit of the ignition system and arearranged to render the ignition system inoperative during said timeinterval. As shown in the drawing, the ignition system thus comprisesthe battery l, switch 9, lead 29, spring strip 3|,

2 aosaaea contacts 25, 26, 21, 28, lead 32, coil 33 and lead 34 to theusual breaker mechanism indicated generally at 35. Contacts 25, 26 and21, 28 are controlled by a coil 36 adapted to attract an armature 31 onthe spring strip 3i which carries contacts26 and 21. Coil 36 is arrangedto be energized when the switch 9 and the contacts i3, M are closed, byvirtue of the leads 38 and 39 which connect the coil 36 in parallel withthe starting switch coil 8. It will thusbe seen that when the switch 9is closed, if the contacts l3,

l4 are closed, coil 36 will be energized, com-' pleting the ignitioncircuit through contacts 25, 26; and if contacts I3, M be opened, thecoil 36 is deenergized and the ignition circuit is completed throughcontacts 21, 28. However, when the contact I4 is vibrating during thetime delay period, coil 36 will be intermittently actuated to vibratethe armature 31 thus causing contacts 26 and 21 to flutter and preventeifective closure of the ignition circuit. It will be .understood thatsince there is no condenser shunted around these contacts, thepulsations of current caused by this fluttering action are ineffectiveto energize the ignition coil.

' In operation of the device, closure of the the ignition circuit forrunning purposes. If a successful start is secured, the generator Genergizesthe generator coil 2| to retain the plunger i! in its retractedposition. If a backfire should occur, however, the generator coil timeinterval and then closes contacts l3, l4 to cause reactuation of thestarting mechanism.

During this period of vibration, the coil 8 is not energized to closethe starting switch since said coil is designed to have sumcientself-inductance to prevent actuation thereof until contact l4 comes torest on contact I3. Coil 36,

however, is designed to be actuated by the pulsating currents-caused bythe vibration of contact l4 on contact l3, thus causing fluttering ofcontacts 26 and 21 and rendering the ignition inoperative. Back-firingof the engine during this time intervalis therefore prevented and theengine consequently comes to rest before th3reactuation of the startingmechanism takes place.

Although but'one embodiment of the invention has been shown and,described in detail, it

will be understood that various other embodiments are possible and thatvarious changes maybe madein the construction of the parts and in theirmethods of cooperation without departing from the spirit 'of theinvention as defined in'the 'claims appended hereto.

What is claimed is:.-- 6 .,1-. In combination with an internalcombustion engine, an ignition system and an automatic startingmechanism. therefor, means for rendering the ignition system andautomatic starting mechanism inoperative for a predetermined periodafter a backfire of the engine occurs, whereby the engine is permited tocome completely to rest before reactuation thereof.

2. In combination with an 'internalcombustion engine and an ignitionsystem therefor, a plurality of contacts controlling said ignitionsystem, and means for fluttering said contacts for a predetermined timeafter forward rotation of the engine ceases.

3. In combination with an internal combustion engine, an ignition systemand automatic starting mechanism therefor including means for delayingthe operation of the automatic starting.

mechanism for a time interval after the engine ceases forward rotation,means controlled by said delaying means for preventing operation of theignition system during said time interval.

4. In combination with an internal combustion engine, and an ignitionsystem therefor,

val after forward rotation of the engine ceases,

and means also controlled by said contacts for controlling said ignitionsystem and efiective to prevent ignition during said time interval.

6. An electrical system for internal combustion engines including anignition system, a starting system, controlling means automaticallyoperative in case of engine stall to actuate the starting system, meansfor delaying such actuation until a predetermined time interval afterforward rotation of the engine ceases, and means for rendering saidignition system inoperative durin said predetermined interval.

- 7. An electrical system for internal combustion engines includinganignition system, a starting system, controlling means automaticallyoperative in case of engine stall to actuate the starting system, meansfor delaying such actuation until a predetermined time interval afterforward rotation of the engine ceases, and means controlled by saiddelaying means for preventing operation of the ignition system.

8. An electrical system for internal combustion engines including anignition system, a starting system, controlling means for the startingsystem including a pair of contacts, closure of which causes actuationof thestarting system, means for opening said contacts when the enginestarts and closing .the same when the engine stalls,

' said means being arranged to vibrate said con- DANIEL L. wna'rz.

